Field of the Invention
The present invention relates to sensorless control of a high speed (over 40,000 rpm) brushless direct current motor (hereinafter referred to as high speed motor), and more particularly to a sensorless speed control method of a high speed motor adapted to uniformly adjust the duty of a rectangular signal generated from a reverse electromotive force regardless of rotating speed to thereby provide stable motor control at high speed and to enable a sensorless mode switch.